This timeline highlights important program decisions and upcoming construction activity. Visit current work to check on our progress.
Our program history provides a more detailed description of past milestones. You can also read the Project History Report (pdf 4.5 Mb), which was released in September 2009.
Program timeline
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| 2001 |
Nisqually earthquake damages viaduct.
Viaduct and seawall replacement project begins.
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| 2002 |
Conceptual engineering for replacement begins.
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| 2003 |
Select environmental review alternatives.
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| 2004 |
Release Draft Environmental Impact Statement with five alternatives.
State and city select cut-and-cover tunnel as preferred alternative.
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| 2005 |
State and city refine cut-and-cover tunnel and elevated structure alternatives.
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| 2006 |
Release Supplemental Draft Environmental Impact Statement with two alternatives.
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| 2007 |
Seattle voters reject cut-and-cover tunnel and elevated alternatives.
Moving Forward projects, located in the north and south ends of the viaduct, begin.
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| 2007 - 2008 |
Repair viaduct columns between Columbia Street and Yesler Way.
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| 2008 |
State, county and city, with input from the public, reexamine options for viaduct’s central waterfront section.
Release Environmental Assessment for replacing the viaduct's south end between S. Holgate and S. King streets.
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| 2008 - 2009 |
Relocate electrical lines from the viaduct's south end.
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| 2008 - 2013 |
Transit enhancements and other improvements to keep people and goods moving during south end construction.
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| 2009 |
Governor, County Executive and Mayor recommend replacing the viaduct's central waterfront section with a bored tunnel beneath downtown, new waterfront surface street, transit investments, and downtown city street and waterfront improvements.
Issue Finding of No Significant Impact for viaduct's south end replacement.
State Legislature approves bored tunnel funding.
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| Ongoing |
Maintain and repair the Battery Street Tunnel at the viaduct's north end.
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| 2010 |
Begin construction to replace viaduct's south end between S. Holgate Street and S. King Street.
Release second Supplemental Draft Environmental Impact Statement.
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| 2011 |
Release Final Environmental Impact Statement and issue Record of Decision.
Begin construction of the viaduct's central waterfront replacement.
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| 2013 |
New SR 99 segment south of downtown, between S. Holgate and S. King streets, opens to drivers.
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| 2015 |
New SR 99 segment through downtown Seattle opens to drivers.
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| 2016 |
Remove viaduct along central waterfront. |